A_Morti's Second CB-1

[a_morti]

very surprised, just shows what a few years of research and development can do!

Not really, as the nc29 was a 1990 bike. It's just the difference between race-specced parts and down-specced parts!

[a_morti]

Fitted the nc29 arm and wheel today. Pictures when I'm back in broadband range!

[a_morti]

The only real snag I had was twofold, firstly you have to pass the chain through the swingarm on these arms. Second the arm is a tiny bit longer, so the chain was one link (half a pair) too short. £99.99 lighter a new DID x ring sorted that out.

Had to trim the undertray slightly, take a nick out the corner of the left heel plate, and remove an odd little bit of what might have been crash protection from the inner edge ofthe exhaust can. Didn't take any modification on the frame at all. Happy with the job :-)

[Daveontheedge]

Looks good morti.

[guntherrex]

looking very nice  swinger drops right in no adjustments to the pivot point?

[a_morti]

looking very nice  swinger drops right in no adjustments to the pivot point?

Some more info here:
http://hondacb1.proboards.com/index.cgi?board=CB1Discussion&action=display&thread=130

The arm fits in the frame (just!) and you then just need some new spacers as the CBR uses a thicker pivot bolt.

In that iteration I (my dad) made up a block to hold the shock linkage still, this time I just flipped it round and carefully ground until the linkage was wedged still. Done a couple thousand miles on it and it seems OK though I would definitely agree it's not "proper".

[Daveontheedge]

Any particular advantage to doing this mod or is it primarily for looks? Just curious as everybody keeps talking about the geometry of the bike and how good it is.

[a_morti]

Any particular advantage to doing this mod or is it primarily for looks? Just curious as everybody keeps talking about the geometry of the bike and how good it is.

I would say the new swinging arm is at least 173% stiffer* but actually in total probably a bit heavier than the outgoing arm. It also require a slightly longer (106 from 104) chain so must be marginally longer, extending the wheelbase and benefiting stability / costing a little flickability. But it's all marginal. You get proper swingarm bobbins in case you don't have a mainstand. I do have one but left them be 'cos they look good.

It also allows the 6-spoke wheels with wider tyres. The rear wheel is around 3lb lighter (measured this time), but mainly better because it allows fitment of a 150 or 160 rear, which means you can use modern, radial compounds. But if you want wider tyres with less fuss you can apparently use CBR600F2 wheels in the original swingarm, although I don't know much about that.

The only disadvantage is that the arm is so much bigger, you can sometimes feel it against the heel of your left boot.

So yes - pretty much just for the look!

* Only believe the statistics you made up yourself

[Daveontheedge]

Interesting. I would have only guessed 170% stiffer, but I guess I should allow for some variances in the alloy...

[a_morti]

Interesting. I would have only guessed 170% stiffer, but I guess I should allow for some variances in the alloy...

See, your average rider would only notice the first 170%...
 

[a_morti]

So, what do we think about CB-1 / café racer stylee? I haven't ridden it yet, so no idea what the ergonomics are like, but the look... hmm, I like it.

[a_morti]

Well a short ride showed up wht I expected. The bars were too low in relation to the low seat.

APEX BAR RISERS | eBay UK

I reckon that'll do 

[a_morti]

[a_morti]

Fitted 110 mains today (in place of 105). This was after changing the air filter for a home-made uni-foam element, which had caused it to bog down around 6-8k rpm in the higher gears, but could be cured by adding choke.

I only got chance for a short test-ride, but it definitely doesn't seem to be worse. At lower speeds when cracking the throttle open and at the problem area with any openings, it seems to be much better / more responsive. Happy Morti Just have to wait to see what it does to the fuel consumption And see if it makes any further problems when I finally get round to fitting those camshafts.

Little things like this also make me happy :smoke: Yes I know they are stainless and that's verboten, but frankly I don't really care. The half bolts are shouldered like originals and all went in with plenty of copper grease to inhibit corrosion, so I am happy enough with it.



I also haven't taken any pictures of the new height-adjustable handlebars. Much nicer riding position, although I find the bars themselves look a little clunky.